Method for removing a pore-generating material from an uncured low-k dielectric film

ABSTRACT

A method of forming a porous low dielectric constant (low-k) dielectric film on a substrate is described, wherein the dielectric constant of the low-k dielectric film is less than a value of approximately 4. The method comprises exposing the low-k dielectric film to infrared (IR) radiation and adjusting a residual amount of cross-linking inhibitor, such as pore-generating material, within the low-k dielectric film.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to pending U.S. patent application Ser. No.11/269,581, entitled “MULTI-STEP SYSTEM AND METHOD FOR CURING ADIELECTRIC FILM”, filed on Nov. 9, 2005, and pending U.S. patentapplication Ser. No. 11/269,581, entitled “THERMAL PROCESSING SYSTEM FORCURING DIELECTRIC FILMS”, filed on Sep. 8, 2006. Further, thisapplication is related to co-pending U.S. patent application Ser. No.12/043,772, entitled “METHOD FOR CURING A POROUS LOW DIELECTRIC CONSTANTDIELECTRIC FILM” (TDC-006), filed on Mar. 6, 2008; co-pending U.S.patent application Ser. No. 12/______, entitled “POROUS SiCOH-CONTAININGDIELECTRIC FILM AND A METHOD OF PREPARING” (TDC-008), filed on even dateherewith; and co-pending U.S. patent application Ser. No. 12/______,entitled “METHOD FOR TREATING DIELECTRIC FILM WITH INFRARED RADIATION”(TDC-009), filed on even date herewith. The entire contents of theseapplications are herein incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a method for treating a dielectric film and,more particularly, to a method of treating a low dielectric constant(low-k) dielectric film with electromagnetic (EM) radiation.

2. Description of Related Art

As is known to those in the semiconductor art, interconnect delay is amajor limiting factor in the drive to improve the speed and performanceof integrated circuits (IC). One way to minimize interconnect delay isto reduce interconnect capacitance by using low dielectric constant(low-k) materials as the insulating dielectric for metal wires in the ICdevices. Thus, in recent years, low-k materials have been developed toreplace relatively high dielectric constant insulating materials, suchas silicon dioxide. In particular, low-k films are being utilized forinter-level and intra-level dielectric layers between metal wires insemiconductor devices. Additionally, in order to further reduce thedielectric constant of insulating materials, material films are formedwith pores, i.e., porous low-k dielectric films. Such low-k films can bedeposited by a spin-on dielectric (SOD) method similar to theapplication of photo-resist, or by chemical vapor deposition (CVD).Thus, the use of low-k materials is readily adaptable to existingsemiconductor manufacturing processes.

Low-k materials are less robust than more traditional silicon dioxide,and the mechanical strength deteriorates further with the introductionof porosity. The porous low-k films can easily be damaged during plasmaprocessing, thereby making desirable a mechanical strengthening process.It has been understood that enhancement of the material strength ofporous low-k dielectrics is essential for their successful integration.Aimed at mechanical strengthening, alternative curing techniques arebeing explored to make porous low-k films more robust and suitable forintegration.

The curing of a polymer includes a process whereby a thin film depositedfor example using spin-on or vapor deposition (such as chemical vapordeposition CVD) techniques, is treated in order to cause cross-linkingwithin the film. During the curing process, free radical polymerizationis understood to be the primary route for cross-linking. As polymerchains cross-link, mechanical properties, such as for example theYoung's modulus, the film hardness, the fracture toughness and theinterfacial adhesion, are improved, thereby improving the fabricationrobustness of the low-k film.

As there are various strategies to forming porous dielectric films withultra low dielectric constant, the objectives of post-depositiontreatments (curing) may vary from film to film, including for examplethe removal of moisture, the removal of solvents, the burn-out ofporogens used to form the pores in the porous dielectric film, theimprovement of the mechanical properties for such films, and so on.

Low dielectric constant (low k) materials are conventionally thermallycured at a temperature in the range of 300° C. to 400° C. for CVD films.For instance, furnace curing has been sufficient in producing strong,dense low-k films with a dielectric constant greater than approximately2.5. However, when processing porous dielectric films (such as ultralow-k films) with a high level of porosity, the degree of cross-linkingachievable with thermal treatment (or thermal curing) is no longersufficient to produce films of adequate strength for a robustinterconnect structure.

During thermal curing, an appropriate amount of energy is delivered tothe dielectric film without damaging the dielectric film. Within thetemperature range of interest, however, only a small amount of freeradicals can be generated. Only a small amount of thermal energy canactually be absorbed in the low-k films to be cured due to the thermalenergy lost in the coupling of heat to the substrate and the heat lossin the ambient environment. Therefore, high temperatures and long curingtimes are required for typical low-k furnace curing. But even with ahigh thermal budget, the lack of initiator generation in the thermalcuring and the presence of a large amount of methyl termination in theas-deposited low-k film can make it very difficult to achieve thedesired degree of cross-linking.

SUMMARY OF THE INVENTION

The invention relates to a method for treating a dielectric film and,more particularly, to a method of curing a low dielectric constant(low-k) dielectric film.

The invention further relates to a method of treating a low-k dielectricfilm with electromagnetic (EM) radiation.

According to an embodiment, a method of curing a low dielectric constant(low-k) dielectric film on a substrate is described, wherein thedielectric constant of the low-k dielectric film is less than a value ofapproximately 4. The method comprises exposing the low-k dielectric filmto infrared (IR) radiation and ultraviolet (UV) radiation.

According to another embodiment, a method of curing a low dielectricconstant (low-k) dielectric film on a substrate is described,comprising: forming a low-k dielectric film on a substrate; exposing thelow-k dielectric film to a first infrared (IR) radiation; exposing thelow-k dielectric film to ultraviolet (UV) radiation following theexposure to the first IR radiation; and exposing the low-k dielectricfilm to a second infrared (IR) radiation following the exposure to theUV radiation, wherein the dielectric constant of the low-k dielectricfilm is less than a value of approximately 4.

According to another embodiment, a method of curing a low dielectricconstant (low-k) film on a substrate is described, comprising: forming alow-k dielectric film on a substrate, the low-k dielectric filmcomprising a structure-forming material and a pore-generating material;exposing the low-k dielectric film to infrared (IR) radiation for afirst time duration; and during the first time duration, exposing thelow-k dielectric film to ultraviolet (UV) radiation for a second timeduration, wherein the second time duration is a fraction of the firsttime duration, and wherein the second time duration begins at a firsttime following the start of the first time duration and ends at a secondtime preceding the end of the first time duration.

According to yet another embodiment, a method of curing a low dielectricconstant (low-k) dielectric film on a substrate is described,comprising: forming a low-k dielectric film on a substrate, the low-kdielectric film comprising a structure-forming material and apore-generating material; substantially removing the pore-generatingmaterial from the low-k dielectric film to form a porous low-kdielectric film; generating cross-linking initiators in the porous low-kdielectric film following the removing; and cross-linking the porouslow-k dielectric film following the generating the cross-linkinginitiators.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a flow chart of a method of treating a dielectric filmaccording to an embodiment;

FIG. 2 is a flow chart of a method of treating a dielectric filmaccording to another embodiment;

FIG. 3 is a flow chart of a method of treating a dielectric filmaccording to another embodiment;

FIG. 4 is a flow chart of a method of treating a dielectric filmaccording to another embodiment;

FIGS. 5A through 5C are schematic representations of a transfer systemfor a drying system and a curing system according to an embodiment;

FIG. 6 is a schematic cross-sectional view of a drying system accordingto another embodiment; and

FIG. 7 is a schematic cross-sectional view of a curing system accordingto another embodiment.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the following description, in order to facilitate a thoroughunderstanding of the invention and for purposes of explanation and notlimitation, specific details are set forth, such as a particulargeometry of the processing system and descriptions of various componentsand processes. However, it should be understood that the invention maybe practiced in other embodiments that depart from these specificdetails.

The inventors recognized that alternative curing methods address some ofthe deficiencies of thermal curing alone. For instance, alternativecuring methods are more efficient in energy transfer, as compared tothermal curing processes, and the higher energy levels found in the formof energetic particles, such as accelerated electrons, ions, orneutrals, or in the form of energetic photons, can easily exciteelectrons in a low-k dielectric film, thus efficiently breaking chemicalbonds and dissociating side groups. These alternative curing methodsfacilitate the generation of cross-linking initiators (free radicals)and can improve the energy transfer required in actual cross-linking. Asa result, the degree of cross-linking can be increased at a reducedthermal budget.

Additionally, the inventors have realized that, when film strengthbecomes a greater issue for the integration of low-k and ultra-low-k(ULK) dielectric films (dielectric constant less than approximately2.5), alternative curing methods can improve the mechanical propertiesof such films. For example, electron beam (EB), ultraviolet (UV)radiation, infrared (IR) radiation and microwave (MW) radiation may beused to cure low-k films and ULK films in order to improve mechanicalstrength, while not sacrificing the dielectric property and filmhydrophobicity.

However, although EB, UV, IR and MW curing all have their own benefits,these techniques also have limitations. High energy curing sources suchas EB and UV can provide high energy levels to generate more than enoughcross-linking initiators (free radicals) for cross-linking, which leadsto much improved mechanical properties under complementary substrateheating. On the other hand, electrons and UV photons can causeindiscriminate dissociation of chemical bonds, which may adverselydegrade the desired physical and electrical properties of the film, suchas loss of hydrophobicity, increased residual film stress, collapse ofpore structure, film densification and increased dielectric constant.Furthermore, low energy curing sources, such as MW curing, can providesignificant improvements mostly in the heat transfer efficiency, but inthe meantime have side effects, such as for example arcing or transistordamage (MW).

According to an embodiment, a method of curing a low dielectric constant(low-k) dielectric film on a substrate is described, wherein thedielectric constant of the low-k dielectric film is less than a value ofapproximately 4. The method comprises exposing the low-k dielectric filmto non-ionizing, electromagnetic (EM) radiation, including ultraviolet(UV) radiation and infrared (IR) radiation. The UV exposure may comprisea plurality of UV exposures, wherein each UV exposure may or may notinclude a different intensity, power, power density, or wavelengthrange, or any combination of two or more thereof. The IR exposure maycomprise a plurality of IR exposures, wherein each IR exposure may ormay not include a different intensity, power, power density, orwavelength range, or any combination of two or more thereof.

During the UV exposure, the low-k dielectric film may be heated byelevating the temperature of the substrate to a UV thermal temperatureranging from approximately 200 degrees C. to approximately 600 degreesC. Alternatively, the UV thermal temperature ranges from approximately300 degrees C. to approximately 500 degrees C. Alternatively, the UVthermal temperature ranges from approximately 350 degrees C. toapproximately 450 degrees C. Substrate thermal heating may be performedby conductive heating, convective heating, or radiative heating, or anycombination of two or more thereof.

During the IR exposure, the low-k dielectric film may be heated byelevating the temperature of the substrate to an IR thermal temperatureranging from approximately 200 degrees C. to approximately 600 degreesC. Alternatively, the IR thermal temperature ranges from approximately300 degrees C. to approximately 500 degrees C. Alternatively, the IRthermal temperature ranges from approximately 350 degrees C. toapproximately 450 degrees C. Substrate thermal heating may be performedby conductive heating, convective heating, or radiative heating, or anycombination of two or more thereof.

Additionally, thermal heating may take place before UV exposure, duringUV exposure, or after UV exposure, or any combination of two or morethereof. Additionally yet, thermal heating may take place before IRexposure, during IR exposure, or after IR exposure, or any combinationof two or more thereof. Thermal heating may be performed by conductiveheating, convective heating, or radiative heating, or any combination oftwo or more thereof.

Further, IR exposure may take place before the UV exposure, during theUV exposure, or after the UV exposure, or any combination of two or morethereof. Further yet, UV exposure may take place before the IR exposure,during the IR exposure, or after the IR exposure, or any combination oftwo or more thereof.

Preceding the UV exposure or the IR exposure or both, the low-kdielectric film may be heated by elevating the temperature of thesubstrate to a pre-thermal treatment temperature ranging fromapproximately 200 degrees C. to approximately 600 degrees C.Alternatively, the pre-thermal treatment temperature ranges fromapproximately 300 degrees C. to approximately 500 degrees C. and,desirably, the pre-thermal treatment temperature ranges fromapproximately 350 degrees C. to approximately 450 degrees C.

Following the UV exposure or the IR exposure or both, the low-kdielectric film may be heated by elevating the temperature of thesubstrate to a post-thermal treatment temperature ranging fromapproximately 200 degrees C. to approximately 600 degrees C.Alternatively, the post-thermal treatment temperature ranges fromapproximately 300 degrees C. to approximately 500 degrees C. and,desirably, the post-thermal treatment temperature ranges fromapproximately 350 degrees C. to approximately 450 degrees C.

Referring now to FIG. 1, a method of treating a dielectric film on asubstrate is described according to another embodiment. The substrate tobe treated may be a semiconductor, a metallic conductor, or any othersubstrate to which the dielectric film is to be formed upon. Thedielectric film can have a dielectric constant value (before dryingand/or curing, or after drying and/or curing, or both) less than thedielectric constant of SiO₂, which is approximately 4 (e.g., thedielectric constant for thermal silicon dioxide can range from 3.8 to3.9). In various embodiments of the invention, the dielectric film mayhave a dielectric constant (before drying and/or curing, or after dryingand/or curing, or both) of less than 3.0, a dielectric constant of lessthan 2.5, a dielectric constant of less than 2.2, or a dielectricconstant of less than 1.7.

The dielectric film may be described as a low dielectric constant(low-k) film or an ultra-low-k film. The dielectric film may include atleast one of an organic, inorganic, and inorganic-organic hybridmaterial. Additionally, the dielectric film may be porous or non-porous.

The dielectric film may, for instance, include a single phase or dualphase porous low-k film that includes a structure-forming material and apore-generating material. The structure-forming material may include anatom, a molecule, or fragment of a molecule that is derived from astructure-forming precursor. The pore-generating material may include anatom, a molecule, or fragment of a molecule that is derived from apore-generating precursor (e.g., porogen). The single phase or dualphase porous low-k film may have a higher dielectric constant prior toremoval of the pore-generating material than following the removal ofthe pore-generating material.

For example, forming a single phase porous low-k film may includedepositing a structure-forming molecule having a pore-generatingmolecular side group weakly bonded to the structure-forming molecule ona surface of a substrate. Additionally, for example, forming a dualphase porous low-k film may include co-polymerizing a structure-formingmolecule and a pore-generating molecule on a surface of a substrate.

Additionally, the dielectric film may have moisture, water, solvent,and/or other contaminants which cause the dielectric constant to behigher prior to drying and/or curing than following drying and/orcuring.

The dielectric film can be formed using chemical vapor deposition (CVD)techniques, or spin-on dielectric (SOD) techniques such as those offeredin the Clean Track ACT 8 SOD and ACT 12 SOD coating systems commerciallyavailable from Tokyo Electron Limited (TEL). The Clean Track ACT 8 (200mm) and ACT 12 (300 mm) coating systems provide coat, bake, and curetools for SOD materials. The track system can be configured forprocessing substrate sizes of 100 mm, 200 mm, 300 mm, and greater. Othersystems and methods for forming a dielectric film on a substrate asknown to those skilled in the art of both spin-on dielectric technologyand CVD dielectric technology are suitable for the invention.

For example, the dielectric film may include an inorganic,silicate-based material, such as oxidized organosilane (or organosiloxane), deposited using CVD techniques. Examples of such filmsinclude Black Diamond™ CVD organosilicate glass (OSG) films commerciallyavailable from Applied Materials, Inc., or Coral™ CVD films commerciallyavailable from Novellus Systems.

Additionally, for example, porous dielectric films can includesingle-phase materials, such as a silicon oxide-based matrix havingterminal organic side groups that inhibit cross-linking during a curingprocess to create small voids (or pores). Additionally, for example,porous dielectric films can include dual-phase materials, such as asilicon oxide-based matrix having inclusions of organic material (e.g.,a porogen) that is decomposed and evaporated during a curing process.

Alternatively, the dielectric film may include an inorganic,silicate-based material, such as hydrogen silsesquioxane (HSQ) or methylsilsesquioxane (MSQ), deposited using SOD techniques. Examples of suchfilms include FOx HSQ commercially available from Dow Corning, XLKporous HSQ commercially available from Dow Corning, and JSR LKD-5109commercially available from JSR Microelectronics.

Still alternatively, the dielectric film can include an organic materialdeposited using SOD techniques. Examples of such films include SiLK-I,SiLK-J, SiLK-H, SiLK-D, porous SiLK-T, porous SiLK-Y, and porous SiLK-Zsemiconductor dielectric resins commercially available from DowChemical, and FLARE™, and Nanoglass® commercially available fromHoneywell.

The method includes a flow chart 500 beginning in 510 with optionallydrying the dielectric film on the substrate in a first processingsystem. The first processing system may include a drying systemconfigured to remove, or partially remove, one or more contaminants inthe dielectric film, including, for example, moisture, water, solvent,pore-generating material, residual pore-generating material,pore-generating molecules, fragments of pore-generating molecules, orany other contaminant that may interfere with a subsequent curingprocess.

In 520, the dielectric film is exposed to UV radiation. The UV exposuremay be performed in a second processing system. The second processingsystem may include a curing system configured to perform a UV-assistedcure of the dielectric film by causing or partially causingcross-linking within the dielectric film in order to, for example,improve the mechanical properties of the dielectric film. Following thedrying process, the substrate can be transferred from the firstprocessing system to the second processing system under vacuum in orderto minimize contamination.

The exposure of the dielectric film to UV radiation may include exposingthe dielectric film to UV radiation from one or more UV lamps, one ormore UV LEDs (light-emitting diodes), or one or more UV lasers, or acombination of two or more thereof. The UV radiation may range inwavelength from approximately 100 nanometers (nm) to approximately 600nm. Alternatively, the UV radiation may range in wavelength fromapproximately 200 nm to approximately 400 nm. Alternatively, the UVradiation may range in wavelength from approximately 150 nm toapproximately 300 nm. Alternatively, the UV radiation may range inwavelength from approximately 170 nm to approximately 240 nm.Alternatively, the UV radiation may range in wavelength fromapproximately 200 nm to approximately 240 nm.

During the exposure of the dielectric film to UV radiation, thedielectric film may be heated by elevating the temperature of thesubstrate to a UV thermal temperature ranging from approximately 200degrees C. to approximately 600 degrees C. Alternatively, the UV thermaltemperature can range from approximately 300 degrees C. to approximately500 degrees C. Alternatively, the UV thermal temperature can range fromapproximately 350 degrees C. to approximately 450 degrees C.Alternatively, before the exposure of the dielectric film to UVradiation or after the exposure of the dielectric film to UV radiationor both, the dielectric film may be heated by elevating the temperatureof the substrate. Heating of the substrate may include conductiveheating, convective heating, or radiative heating, or any combination oftwo or more thereof.

Optionally, during the exposure of the dielectric film to UV radiation,the dielectric film may be exposed to IR radiation. The exposure of thedielectric film to IR radiation may include exposing the dielectric filmto IR radiation from one or more IR lamps, one or more IR LEDs (lightemitting diodes), or one or more IR lasers, or a combination of two ormore thereof. The IR radiation may range in wavelength fromapproximately 1 micron to approximately 25 microns. Alternatively, theIR radiation may range in wavelength from approximately 2 microns toapproximately 20 microns. Alternatively, the IR radiation may range inwavelength from approximately 8 microns to approximately 14 microns.Alternatively, the IR radiation may range in wavelength fromapproximately 8 microns to approximately 12 microns. Alternatively, theIR radiation may range in wavelength from approximately 9 microns toapproximately 10 microns.

In 530, the dielectric film is exposed to IR radiation. The exposure ofthe dielectric film to IR radiation may include exposing the dielectricfilm to IR radiation from one or more IR lamps, one or more IR LEDs(light emitting diodes), or one or more IR lasers, or both. The IRradiation may range in wavelength from approximately 1 micron toapproximately 25 microns. Alternatively, the IR radiation may range inwavelength from approximately 2 microns to approximately 20 microns.Alternatively, the IR radiation may range in wavelength fromapproximately 8 microns to approximately 14 microns. Alternatively, theIR radiation may range in wavelength from approximately 8 microns toapproximately 12 microns. Alternatively, the IR radiation may range inwavelength from approximately 9 microns to approximately 10 microns. TheIR exposure may take place before the UV exposure, during the UVexposure, or after the UV exposure, or any combination of two or morethereof.

Furthermore, during the exposure of the dielectric film to IR radiation,the dielectric film may be heated by elevating the temperature of thesubstrate to an IR thermal treatment temperature ranging fromapproximately 200 degrees C. to approximately 600 degrees C.Alternatively, the IR thermal treatment temperature can range fromapproximately 300 degrees C. to approximately 500 degrees C.Alternatively yet, the IR thermal treatment temperature can range fromapproximately 350 degrees C. to approximately 450 degrees C.Alternatively, before the exposure of the dielectric film to IRradiation or after the exposure of the dielectric film to IR radiationor both, the dielectric film may be heated by elevating the temperatureof the substrate. Heating of the substrate may include conductiveheating, convective heating, or radiative heating, or any combination oftwo or more thereof.

As described above, during the IR exposure, the dielectric film may beheated through absorption of IR energy. However, the heating may furtherinclude conductively heating the substrate by placing the substrate on asubstrate holder, and heating the substrate holder using a heatingdevice. For example, the heating device may include a resistive heatingelement.

The inventors have recognized that the energy level (hν) delivered canbe varied during different stages of the curing process. The curingprocess can include mechanisms for the removal of moisture and/orcontaminants, the removal of pore-generating material, the decompositionof pore-generating material, the generation of cross-linking initiators,the cross-linking of the dielectric film, and the diffusion of thecross-linking initiators. Each mechanism may require a different energylevel and rate at which energy is delivered to the dielectric film.

For instance, during the removal of pore-generating material, theremoval process may be facilitated by photon absorption at IRwavelengths. The inventors have discovered that IR exposure assists theremoval of pore-generating material more efficiently than thermalheating or UV exposure.

Additionally, for instance, during the removal of pore-generatingmaterial, the removal process may be assisted by decomposition of thepore-generating material. The removal process may include IR exposurethat is complemented by UV exposure. The inventors have discovered thatUV exposure may assist a removal process having IR exposure bydissociating bonds between pore-generating material (e.g.,pore-generating molecules and/or pore-generating molecular fragments)and the structure-forming material. For example, the removal and/ordecomposition processes may be assisted by photon absorption at UVwavelengths (e.g., about 300 nm to about 450 nm).

Furthermore, for instance, during the generation of cross-linkinginitiators, the initiator generation process may be facilitated by usingphoton and phonon induced bond dissociation within the structure-formingmaterial. The inventors have discovered that the initiator generationprocess may be facilitated by UV exposure. For example, bonddissociation can require energy levels having a wavelength less than orequal to approximately 300 to 400 nm.

Further yet, for instance, during cross-linking, the cross-linkingprocess can be facilitated by thermal energy sufficient for bondformation and reorganization. The inventors have discovered thatcross-linking may be facilitated by IR exposure or thermal heating orboth. For example, bond formation and reorganization may require energylevels having a wavelength of approximately 9 microns which, forexample, corresponds to the main absorbance peak in siloxane-basedorganosilicate low-k materials.

The drying process for the dielectric film, the IR exposure of thedielectric film, and the UV exposure of the dielectric film may beperformed in the same processing system, or each may be performed inseparate processing systems. For example, the drying process may beperformed in the first processing system and the IR exposure and the UVexposure may be performed in the second processing system.Alternatively, for example, the IR exposure of the dielectric film maybe performed in a different processing system than the UV exposure. TheIR exposure of the dielectric film may be performed in a thirdprocessing system, wherein the substrate can be transferred from thesecond processing system to the third processing system under vacuum inorder to minimize contamination.

Additionally, following the optional drying process, the UV exposureprocess, and the IR exposure process, the dielectric film may optionallybe post-treated in a post-treatment system configured to modify thecured dielectric film. For example, post-treatment may include thermalheating the dielectric film. Alternatively, for example, post-treatmentmay include spin coating or vapor depositing another film on thedielectric film in order to promote adhesion for subsequent films orimprove hydrophobicity. Alternatively, for example, adhesion promotionmay be achieved in a post-treatment system by lightly bombarding thedielectric film with ions. Moreover, the post-treatment may compriseperforming one or more of depositing another film on the dielectricfilm, cleaning the dielectric film, or exposing the dielectric film toplasma.

Referring now to FIG. 2, a method of treating a dielectric film on asubstrate is described according to another embodiment. The methodincludes a flow chart 600 beginning in 610 with forming a dielectricfilm, such as a low-k dielectric film, on the substrate. Optionally, adrying process may be performed to remove, or partially remove, one ormore contaminants in the dielectric film, including, for example,moisture, solvent, or any other contaminant that may interfere withproducing a high quality low-k dielectric film, or performing asubsequent process.

In 620, the dielectric film is exposed to first IR radiation. Forexample, the exposure of the dielectric film to the first IR radiationmay facilitate the full removal or partial removal of moisture, water,contaminants, pore-generating material, residual pore-generatingmaterial, pore-generating material including pore-generating moleculesand/or fragments of pore-generating molecules, cross-linking inhibitors,or residual cross-linking inhibitors, or any combination of two or morethereof from the dielectric film. The exposure of the dielectric filmmay be performed for a time duration sufficiently long to substantiallyremove all moisture, water, contaminants, pore-generating material,residual pore-generating material, pore-generating material includingpore-generating molecules and/or fragments of pore-generating molecules,cross-linking inhibitors, and residual cross-linking inhibitors, or anycombination of two or more thereof from the dielectric film.

The exposure of the dielectric film to first IR radiation may includeexposing the dielectric film to polychromatic IR radiation,monochromatic IR radiation, pulsed IR radiation, or continuous wave IRradiation, or a combination of two or more thereof. For example, theexposure of the dielectric film to first IR radiation may includeexposing the dielectric film to IR radiation from one or more IR lamps,one or more IR LEDs (light emitting diodes), or one or more IR lasers,or a combination thereof. The first IR radiation may comprise a powerdensity ranging up to about 20 W/cm². For example, the first IRradiation may comprise a power density ranging from about 1 W/cm² toabout 20 W/cm². The first IR radiation may range in wavelength fromapproximately 1 micron to approximately 25 microns. Alternatively, thefirst IR radiation may range in wavelength from approximately 2 micronsto approximately 20 microns. Alternatively, the first IR radiation mayrange in wavelength from approximately 8 microns to approximately 14microns. Alternatively, the first IR radiation may range in wavelengthfrom approximately 8 microns to approximately 12 microns. Alternatively,the first IR radiation may range in wavelength from approximately 9microns to approximately 10 microns. The first IR power density, or thefirst IR wavelength, or both, may be varied during the first IRexposure.

Optionally, during the first IR exposure, the dielectric film may beheated by elevating the temperature of the substrate to a first IRthermal treatment temperature ranging from approximately 200 degrees C.to approximately 600 degrees C. Alternatively, the first IR thermaltreatment temperature can range from approximately 300 degrees C. toapproximately 500 degrees C. Alternatively yet, the first IR thermaltreatment temperature can range from approximately 350 degrees C. toapproximately 450 degrees C.

In 630, the dielectric film is exposed to UV radiation following thefirst IR exposure. For example, the exposure of the substrate to the UVradiation may facilitate the generation of cross-linking initiators (orfree radicals) in the dielectric film.

The exposure of the dielectric film to UV radiation may include exposingthe dielectric film to polychromatic UV radiation, monochromatic UVradiation, pulsed UV radiation, or continuous wave UV radiation, or acombination of two or more thereof. For example, the exposure of thedielectric film to UV radiation may include exposing the dielectric filmto UV radiation from one or more UV lamps, one or more UV LEDs (lightemitting diodes), or one or more UV lasers, or a combination thereof.The UV radiation may comprise a power density ranging from approximately0.1 mW/cm² to approximately 2000 mW/cm². The UV radiation may range inwavelength from approximately 100 nanometers (nm) to approximately 600nm. Alternatively, the UV radiation may range in wavelength fromapproximately 200 nm to approximately 400 nm. Alternatively, the UVradiation may range in wavelength from approximately 150 nm toapproximately 300 nm. Alternatively, the UV radiation may range inwavelength from approximately 170 nm to approximately 240 nm.Alternatively, the UV radiation may range in wavelength fromapproximately 200 nm to approximately 240 nm.

Optionally, during the UV exposure, the dielectric film may be heated byelevating the temperature of the substrate to a UV thermal treatmenttemperature ranging from approximately 200 degrees C. to approximately600 degrees C. Alternatively, the UV thermal treatment temperature canrange from approximately 300 degrees C. to approximately 500 degrees C.Alternatively yet, the UV thermal treatment temperature can range fromapproximately 350 degrees C. to approximately 450 degrees C.

In 640, the dielectric film is exposed to second IR radiation. Forexample, the exposure of the dielectric film to the second IR radiationmay facilitate cross-linking of the dielectric film.

The exposure of the dielectric film to second IR radiation may includeexposing the dielectric film to polychromatic IR radiation,monochromatic IR radiation, pulsed IR radiation, or continuous wave IRradiation, or a combination of two or more thereof. For example, theexposure of the dielectric film to second IR radiation may includeexposing the dielectric film to IR radiation from one or more IR lamps,one or more IR LEDs (light emitting diodes), or one or more IR lasers,or a combination thereof. The second IR radiation may comprise a powerdensity ranging up to about 20 W/cm². For example, the second IRradiation may comprise a power density ranging from about 1 W/cm² toabout 20 W/cm². The second IR radiation may range in wavelength fromapproximately 1 micron to approximately 25 microns. Alternatively, thesecond IR radiation may range in wavelength from approximately 2 micronsto approximately 20 microns. Alternatively, the second IR radiation mayrange in wavelength from approximately 8 microns to approximately 14microns. Alternatively, the second IR radiation may range in wavelengthfrom approximately 8 microns to approximately 12 microns. Alternatively,the second IR radiation may range in wavelength from approximately 9microns to approximately 10 microns. The second IR power density, or thesecond IR wavelength, or both may be varied during the second IRexposure.

Optionally, during the second IR exposure, the dielectric film may beheated by elevating the temperature of the substrate to a second IRthermal treatment temperature ranging from approximately 200 degrees C.to approximately 600 degrees C. Alternatively, the second IR thermaltreatment temperature can range from approximately 300 degrees C. toapproximately 500 degrees C. Alternatively yet, the second IR thermaltreatment temperature can range from approximately 350 degrees C. toapproximately 450 degrees C.

Optionally, during at least a portion of the first IR exposure, thedielectric film may be exposed to second UV radiation. For example, theexposure of the dielectric film to the second UV radiation mayfacilitate the breaking or dissociating of bonds in the dielectric filmin order to assist the removal of various materials described above. Thesecond UV radiation may comprise a UV power density ranging fromapproximately 0.1 mW/cm² to approximately 2000 mW/cm². The second UVradiation may range in wavelength from approximately 100 nanometers (nm)to approximately 600 nm. Alternatively, the second UV radiation mayrange in wavelength from approximately 200 nm to approximately 400 nm.Alternatively, the second UV radiation may range in wavelength fromapproximately 150 nm to approximately 300 nm. Alternatively, the secondUV radiation may range in wavelength from approximately 170 nm toapproximately 240 nm. Alternatively, the second UV radiation may rangein wavelength from approximately 200 nm to approximately 240 nm.

Optionally, during at least a portion of the UV exposure, the dielectricfilm may be exposed to third IR radiation. The third IR radiation maycomprise a power density ranging up to about 20 W/cm². For example, thethird IR radiation may comprise a power density ranging from about 1W/cm² to about 20 W/cm². The third IR radiation may range in wavelengthfrom approximately 1 micron to approximately 25 microns. Alternatively,the third IR radiation may range in wavelength from approximately 2microns to approximately 20 microns. Alternatively, the third IRradiation may range in wavelength from approximately 8 microns toapproximately 14 microns. Alternatively, the third IR radiation mayrange in wavelength from approximately 8 microns to approximately 12microns. Alternatively, the third IR radiation may range in wavelengthfrom approximately 9 microns to approximately 10 microns. The third IRpower density, or the third IR wavelength, or both may be varied duringthe third IR exposure.

Preceding the UV exposure or the first IR exposure or both, thedielectric film may be heated by elevating the temperature of thesubstrate to a pre-thermal treatment temperature ranging fromapproximately 200 degrees C. to approximately 600 degrees C.Alternatively, the pre-thermal treatment temperature ranges fromapproximately 300 degrees C. to approximately 500 degrees C. and,desirably, the pre-thermal treatment temperature ranges fromapproximately 350 degrees C. to approximately 450 degrees C.

Following the UV exposure or the second IR exposure or both, thedielectric film may be heated by elevating the temperature of thesubstrate to a post-thermal treatment temperature ranging fromapproximately 200 degrees C. to approximately 600 degrees C.Alternatively, the post-thermal treatment temperature ranges fromapproximately 300 degrees C. to approximately 500 degrees C. and,desirably, the post-thermal treatment temperature ranges fromapproximately 350 degrees C. to approximately 450 degrees C.

According to another embodiment, a method of curing a low dielectricconstant (low-k) film on a substrate is described. The method comprisesforming a low-k dielectric film on a substrate, wherein the low-kdielectric film comprises a structure-forming material and apore-generating material. The low-k dielectric film is exposed toinfrared (IR) radiation for a first time duration. During the first timeduration, the low-k dielectric film is exposed to ultraviolet (UV)radiation for a second time duration, wherein the second time durationis a fraction of the first time duration, and wherein the second timeduration begins at a first time following the start of the first timeduration and ends at a second time preceding the end of the first timeduration.

Referring to FIG. 3, a method of curing a low dielectric constant(low-k) dielectric film on a substrate is described according to yetanother embodiment. The method comprises a flow chart 700 beginning in710 with forming a low-k dielectric film on a substrate, wherein thelow-k dielectric film comprises a structure-forming material and apore-generating material. In 720, the pore-generating material issubstantially removed from the low-k dielectric film to form a porouslow-k dielectric film. Furthermore, in 720, cross-linking inhibitors maybe substantially removed. The cross-linking inhibitors may includemoisture, water, contaminants, pore-generating material, residualpore-generating material, or pore-generating material includingpore-generating molecules and/or fragments of pore-generating molecules,or any combination of two or more thereof.

In 730, cross-linking initiators are generated in the porous low-kdielectric film following the removal of the pore-generating material.In 740, the structure-forming material of the porous low-k dielectricfilm is cross-linked following the generating the cross-linkinginitiators.

Furthermore, the method may optionally include breaking bonds in thelow-k dielectric film in order to assist the removing.

Referring to FIG. 4, a method of curing a low dielectric constant(low-k) dielectric film on a substrate is described according to yetanother embodiment. The method comprises a flow chart 800 beginning in810 with forming a low-k dielectric film on a substrate, wherein thelow-k dielectric film comprises a structure-forming material and across-linking inhibitor. The cross-linking inhibitor may includemoisture, water, solvent, contaminants, pore-generating material,residual pore-generating material, a weakly bonded side group to thestructure-forming material, pore-generating molecules, or fragments ofpore-generating molecules, or any combination of two or more thereof.For example, the cross-linking inhibitor may comprise a pore-generatingmaterial, wherein the low-k dielectric film having the structure-formingmaterial and the cross-linking inhibitor comprises co-polymerizing astructure-forming molecule and a pore-generating molecule on a surfaceof the substrate. Additionally, for example, the cross-linking inhibitormay comprise a pore-generating material, wherein the low-k dielectricfilm having the structure-forming material and the cross-linkinginhibitor comprises depositing a structure-forming molecule having apore-generating molecular side group weakly bonded to thestructure-forming molecule on a surface of the substrate.

In 820, the low-k dielectric film is exposed to infrared (IR) radiation.The exposure of the low-k dielectric film to IR radiation can compriseexposing the low-k dielectric film to polychromatic IR radiation,monochromatic IR radiation, pulsed IR radiation, or continuous wave IRradiation, or a combination of two or more thereof. The exposure of thelow-k dielectric film to IR radiation can comprise exposing the low-kdielectric film to IR radiation with a wavelength ranging fromapproximately 8 microns to approximately 12 microns.

Optionally, the low-k dielectric film may be exposed to ultraviolet (UV)radiation. The exposure of the low-k dielectric film to UV radiation maycomprise exposing the low-k dielectric film to polychromatic UVradiation, monochromatic UV radiation, pulsed UV radiation, orcontinuous wave UV radiation, or a combination of two or more thereof.The exposure of the low-k dielectric film to UV radiation may compriseexposing the low-k dielectric film to UV radiation with a wavelengthranging from approximately 100 nanometers to approximately 600nanometers. The UV exposure may follow the IR exposure. Alternatively,the UV exposure may occur during part or all of the IR exposure. Forexample, the UV exposure occurring during the IR exposure may comprise awavelength ranging from approximately 300 nanometers to approximately450 nanometers.

In 830, a residual amount of the cross-linking inhibitor is adjusted inorder to tune a mechanical property of the low-k dielectric film, anelectrical property of the low-k dielectric film, an optical property ofthe low-k dielectric film, a pore size of the low-k dielectric film, ora porosity of the low-k dielectric film, or a combination of two or morethereof. The residual amount of cross-linking inhibitor may affect otherproperties including carbon concentration, hydrophobicity, and plasmaresistance.

The mechanical property may comprise an elastic modulus (E), or ahardness (H), or both. The electrical property may comprise a dielectricconstant (k). The optical property may comprise a refractive index (n).

The adjusting of the residual amount of the cross-linking inhibitor maycomprise substantially removing the cross-linking inhibitor from thelow-k dielectric film during the IR exposure. For example, thecross-linking inhibitor may be substantially removed prior to anyexposure of the low-k dielectric film to ultraviolet (UV) radiation.

Alternatively, the adjusting of the residual amount of the cross-linkinginhibitor may comprise adjusting a time duration for the IR exposure, anIR intensity for the IR exposure, or an IR dose for the IR exposure, ora combination of two or more thereof.

Alternatively, the adjusting of the residual amount of the cross-linkinginhibitor may comprise adjusting a time duration for the UV exposureduring the IR exposure, a UV intensity for the UV exposure, or a UV dosefor the UV exposure, or a combination of two or more thereof.

The method may further comprise exposing the low-k dielectric film toultraviolet (UV) radiation following the IR exposure, and exposing thelow-k dielectric film to second IR radiation during the UV exposure.Additionally, the method may further comprise exposing the low-kdielectric film to third IR radiation following the UV exposure.

Furthermore, the method may comprise exposing the low-k dielectric filmto first ultraviolet (UV) radiation following the IR exposure, andexposing the low-k dielectric film to second UV radiation during the IRexposure, wherein the second UV exposure is different than the first UVexposure. The adjusting of the residual amount of the cross-linkinginhibitor may comprise adjusting a time duration for the second UVexposure during the IR exposure, a UV intensity for the second UVexposure, or a UV dose for the second UV exposure, or a combination oftwo or more thereof. The exposure of the dielectric film to the secondUV radiation may comprise a wavelength ranging from approximately 300nanometers to approximately 450 nanometers.

Optionally, the low-k dielectric film may be heated before the IRexposure, during the IR exposure, or after the IR exposure, or anycombination of two or more thereof.

IR treatment(s) may be performed in vacuum conditions or a controlledatmosphere.

According to one example, the structure-forming material may comprisediethoxymethylsilane (DEMS), and the pore-generating material maycomprise a terpene; a norborene; 5-dimethyl-1,4-cyclooctadiene;decahydronaphthalene; ethylbenzene; or limonene; or a combination of twoor more thereof. For example, the pore-generating material may comprisealpha-terpinene (ATRP).

According to another example, a method of preparing a porous low-kdielectric film on a substrate is described. The method comprises:forming a SiCOH-containing dielectric film on a substrate using achemical vapor deposition (CVD) process, wherein the CVD process usesdiethoxymethylsilane (DEMS) and a pore-generating material; exposing theSiCOH-containing dielectric film to IR radiation for a first timeduration sufficiently long to substantially remove the pore-generatingmaterial; exposing the SiCOH-containing dielectric film to UV radiationfor a second time duration following the IR exposure; and heating theSiCOH-containing dielectric film during part or all of said second timeduration.

The exposure of the SiCOH-containing dielectric film to IR radiation cancomprise IR radiation with a wavelength ranging from approximately 9microns to approximately 10 microns (e.g., 9.4 microns). The exposure ofthe SiCOH-containing dielectric film to UV radiation can comprise UVradiation with a wavelength ranging from approximately 170 nanometers toapproximately 240 nanometers (e.g., 222 nm). The heating of theSiCOH-containing dielectric film can comprise heating the substrate to atemperature ranging from approximately 300 degrees C. to approximately500 degrees C.

The IR exposure and the UV exposure may be performed in separate processchambers, or the IR exposure and the UV exposure may be performed in thesame process chamber.

The pore-generating material may comprise a terpene; a norborene;5-dimethyl-1,4-cyclooctadiene; decahydronaphthalene; ethylbenzene; orlimonene; or a combination of two or more thereof. For example, thepore-generating material may comprise alpha-terpinene (ATRP).

Table 1 provides data for a porous low-k dielectric film intended tohave a dielectric constant of about 2.2 to 2.25. The porous low-kdielectric film comprises a porous SiCOH-containing dielectric filmformed with a CVD process using a structure-forming material comprisingdiethoxymethylsilane (DEMS) and a pore-generating material comprisingalpha-terpinene (ATRP). The “Pristine” SiCOH-containing dielectric filmhaving a nominal thickness (Angstroms, A) and refractive index (n) isfirst exposed to IR radiation resulting in a “Post-IR” thickness (A) and“Post-IR” refractive index (n). Thereafter, the “Post-IR”SiCOH-containing dielectric film is exposed to UV radiation while beingthermally heated resulting in a “Post-UV+Heating” thickness (A) and“Post-UV+Heating” refractive index (n).

TABLE 1 Pristine Post-IR UV + Heating Shrinkage Thickness ThicknessThickness Post-IR Post-UV UV Time E (A) n (A) n (A) n (%) (%) (nm) (min)k (GPa) 5860 1.498 5609 1.282 4837 1.34 4.3 17.5 172 10 2.29 5.37 58801.495 5644 1.291 5335 1.309 4 9.3 222 5 2.09 3.69 5951 1.492 5651 1.285285 1.309 5 11.2 222 10 2.11 4.44

Referring still to Table 1, the shrinkage (%) in film thickness isprovided Post-IR and Post-UV+Heating. Additionally, the UV wavelengthand UV exposure time (minutes, min) are provided. Furthermore, thedielectric constant (k) and the elastic modulus (E) (GPa) are providedfor the resultant, cured porous low-k dielectric film. As shown in Table1, the use of IR radiation preceding UV radiation and heating leads todielectric constants less than 2.3 and as low as 2.09. Moreover, a lowdielectric constant, i.e., k=2.11, can be achieved while acceptablemechanical properties, i.e., E=4.44 GPa, can also be achieved.

For comparison purposes, SiCOH-containing dielectric films, formed usingthe same CVD process, were cured without exposure to IR radiation.Without IR exposure, the “Post-UV+Heating” refractive index ranges fromabout 1.408 to about 1.434, which is significantly higher than theresults provided in Table 1. The higher refractive index may indicate anexcess of residual pore-generating material in the film, e.g., lessporous film, and/ot oxidation of the film.

According to yet another example, a method of preparing a porous low-kdielectric film on a substrate is described. The method comprises:forming a SiCOH-containing dielectric film on a substrate using achemical vapor deposition (CVD) process, wherein the CVD process usesdiethoxymethylsilane (DEMS) and a pore-generating material; exposing theSiCOH-containing dielectric film to first IR radiation for a first timeduration sufficiently long to substantially remove the pore-generatingmaterial; exposing the SiCOH-containing dielectric film to UV radiationfor a second time duration following the first IR exposure; exposing theSiCOH-containing dielectric film to second IR radiation for a third timeduration during the UV exposure; and exposing the SiCOH-containingdielectric film to third IR radiation for a fourth time durationfollowing the UV exposure.

The method may further comprise heating the SiCOH-containing dielectricfilm during part or all of the second time duration. Additionally, thesecond time duration may coincide with the second time duration.

The exposure of the SiCOH-containing dielectric film to first IRradiation can comprise IR radiation with a wavelength ranging fromapproximately 9 microns to approximately 10 microns (e.g., 9.4 microns).The exposure of the SiCOH-containing dielectric film to UV radiation cancomprise UV radiation with a wavelength ranging from approximately 170nanometers to approximately 230 nanometers (e.g., 222 nm). The exposureof the SiCOH-containing dielectric film to second IR radiation cancomprise IR radiation with a wavelength ranging from approximately 9microns to approximately 10 microns (e.g., 9.4 microns). The exposure ofthe SiCOH-containing dielectric film to third IR radiation can compriseIR radiation with a wavelength ranging from approximately 9 microns toapproximately 10 microns (e.g., 9.4 microns). The heating of theSiCOH-containing dielectric film can comprise heating the substrate to atemperature ranging from approximately 300 degrees C. to approximately500 degrees C.

The pore-generating material may comprise a terpene; a norborene;5-dimethyl-1,4-cyclooctadiene; decahydronaphthalene; ethylbenzene; orlimonene; or a combination of two or more thereof. For example, thepore-generating material may comprise alpha-terpinene (ATRP).

Table 2 provides data for a porous low-k dielectric film intended tohave a dielectric constant of about 2.2 to 2.25. The porous low-kdielectric film comprises a porous SiCOH-containing dielectric filmformed with a CVD process using a structure-forming material comprisingdiethoxymethylsilane (DEMS) and a pore-generating material comprisingalpha-terpinene (ATRP). The “Pristine” SiCOH-containing dielectric filmhaving a nominal thickness (Angstroms, A) and refractive index (n) iscured using two processes, namely: (1) a conventional UV/Thermal process(i.e., no IR exposure); and (2) a curing process wherein the pristinefilm is exposed to IR radiation (9.4 micron), followed by exposure to IRradiation (9.4 micron) and UV radiation (222 nm), followed by exposureto IR radiation (9.4 micron).

TABLE 2 Thickness Thickness Shrinkage E H (A) n (A) n Post-(%) k (GPa)(GPa) Pristine Post-UV/Thermal 6100 1.495 5350 1.329 13 2.2 4.51 0.45Post-IR + Pristine UV/IR + IR 6137 1.488 5739 1.282 6.5 2.1 3.99 0.286107 1.5 5473 1.297 10.4 2.1 4.26 0.35 6173 1.498 5483 1.302 11.2 2.14.71 0.46 6135 1.499 5374 1.306 12.4 2.1 4.78 0.48

Table 2 provides the “Post-UV/Thermal” thickness (A) and“Post-UV/Thermal” refractive index (n) for the conventional UV/Thermalprocess, and the “Post-IR+UV/IR+IR” thickness (A) and “Post-IR+UV/IR+IR”refractive index (n) for the IR+UV/IR+IR process. Additionally, theshrinkage (%) in film thickness is provided Post-UV/Thermal andPost-IR+UV/IR+IR. Furthermore, the dielectric constant (k), the elasticmodulus (E) (GPa) and the hardness (H) (GPa) are provided for theresultant, cured porous low-k dielectric film. As shown in Table 2, theuse of IR radiation preceding UV radiation and heating, as well asduring and after the UV exposure, leads to dielectric constants lessthan 2.1. Moreover, a low dielectric constant, i.e., k=2.1, can beachieved while acceptable mechanical properties, i.e., E=4.71 GPa andH=0.46 GPa, can also be achieved. Comparatively speaking, theIR+UV/IR+IR curing process produces a lower dielectric constant (k=2.1)with less film thickness shrinkage. Moreover, the mechanical properties(E and H) are approximately the same for the two curing processes.

As a result, the use of IR exposure and UV exposure can lead to theformation of a diethoxymethylsilane (DEMS)-based, porous dielectric filmcomprising a dielectric constant of about 2.1 or less, a refractiveindex of about 1.31 or less, an elastic modulus of about 4 GPa orgreater, and a hardness of about 0.45 GPa or greater.

Table 3 provides data for a porous low-k dielectric film intended tohave a dielectric constant of about 2. The porous low-k dielectric filmcomprises a porous SiCOH-containing dielectric film formed with a CVDprocess using a structure-forming material comprisingdiethoxymethylsilane (DEMS) and a pore-generating material comprisingalpha-terpinene (ATRP). The pristine SiCOH-containing dielectric film iscured using three processes, namely: (1) a conventional UV/Thermalprocess (i.e., no IR exposure); (2) a curing process wherein thepristine film is exposed to IR radiation only (9.4 micron); (3) a curingprocess wherein the pristine film is exposed to IR radiation (9.4micron) followed by a conventional UV/Thermal process; and (4) a curingprocess wherein the pristine film is exposed to IR radiation (9.4micron), followed by exposure to IR radiation (9.4 micron) and UVradiation (222 nm), followed by exposure to IR radiation (9.4 micron).

TABLE 3 Process type n Shrinkage (%) k E (GPa) H (GPa) UV/Thermal 1.27533 1.92 2.52 0.28 IR only 1.174 15 1.66 1.2 0.1 IR + UV/Thermal 1.172 291.65 2.4 0.33 IR + UV/IR + IR 1.172 26 1.68 2.34 0.28 1.164 29 1.66 2.080.25

Table 3 provides the resulting refractive index (n), shrinkage (%),dielectric constant (k), elastic modulus (E) (GPa) and hardness (H)(GPa) following each of the curing processes. As shown in Table 3, theuse of IR radiation (with or without UV radiation) leads to a dielectricconstant less than 1.7 (as opposed to greater than 1.9). When using onlyIR radiation to cure the pristine film, a low dielectric constant, i.e.,k=1.66, can be achieved while acceptable mechanical properties, i.e.,E=1.2 GPa and H=0.1 GPa, can also be achieved. However, when using IRradiation and UV radiation to cure the pristine film, a low dielectricconstant, i.e., k=1.68, can be achieved while improved mechanicalproperties, i.e., E=2.34 GPa and H=0.28 GPa, can also be achieved.Additionally, the curing processes using IR radiation produce a lowerdielectric constant (k=1.66 to 1.68) with less film thickness shrinkage.Further, when IR radiation is used, the mechanical properties (E and H)can be improved by using UV radiation.

As a result, the use of IR exposure and UV exposure can lead to theformation of a diethoxymethylsilane (DEMS)-based, porous dielectric filmcomprising a dielectric constant of about 1.7 or less, a refractiveindex of about 1.17 or less, an elastic modulus of about 1.5 GPa orgreater, and a hardness of about 0.2 GPa or greater.

According to one embodiment, FIG. 5A shows a processing system 1 fortreating a dielectric film on a substrate, according to one embodiment.The processing system 1 includes a drying system 20, and a curing system10 coupled to the drying system 20. For example, the drying system 10can be configured to remove, or reduce to sufficient levels, one or morecontaminants, pore-generating materials, and/or cross-linking inhibitorsin the dielectric film, including, for example, moisture, water,solvent, contaminants, pore-generating material, residualpore-generating material, a weakly bonded side group to thestructure-forming material, pore-generating molecules, fragments ofpore-generating molecules, cross-linking inhibitors, fragments ofcross-linking inhibitors, or any other contaminant that may interferewith a curing process performed in the curing system 10.

For example, a sufficient reduction of a specific contaminant presentwithin the dielectric film, from prior to the drying process tofollowing the drying process, can include a reduction of approximately10% to approximately 100% of the specific contaminant. The level ofcontaminant reduction may be measured using Fourier transform infrared(FTIR) spectroscopy, or mass spectroscopy. Alternatively, for example, asufficient reduction of a specific contaminant present within thedielectric film can range from approximately 50% to approximately 100%.Alternatively, for example, a sufficient reduction of a specificcontaminant present within the dielectric film can range fromapproximately 80% to approximately 100%.

Referring still to FIG. 5A, the curing system 10 may be configured tocure the dielectric film by causing or partially causing cross-linkingwithin the dielectric film in order to, for example, improve themechanical properties of the dielectric film. Furthermore, the curingsystem 10 may be configured to cure the dielectric film by causing orpartially causing cross-link initiation, removal of pore-generatingmaterial, decomposition of pore-generating material, etc. The curingsystem 10 can include one or more radiation sources configured to exposethe substrate having the dielectric film to electro-magnetic (EM)radiation at multiple EM wavelengths. For example, the one or moreradiation sources can include an infrared (IR) radiation source and anultraviolet (UV) radiation source. The exposure of the substrate to UVradiation and IR radiation can be performed simultaneously,sequentially, or partially over-lapping one another. During sequentialexposure, the exposure of the substrate to UV radiation can, forinstance, precede the exposure of the substrate to IR radiation orfollow the exposure of the substrate to IR radiation or both.Additionally, during sequential exposure, the exposure of the substrateto IR radiation can, for instance, precede the exposure of the substrateto UV radiation or follow the exposure of the substrate to UV radiationor both.

For example, the IR radiation can include an IR radiation source rangingfrom approximately 1 micron to approximately 25 microns. Additionally,for example, the IR radiation may range from about 2 microns to about 20microns, or from about 8 microns to about 14 microns, or from about 8microns to about 12 microns, or from about 9 microns to about 10microns. Additionally, for example, the UV radiation can include a UVwave-band source producing radiation ranging from approximately 100nanometers (nm) to approximately 600 nm. Furthermore, for example, theUV radiation may range from about 200 nm to about 400 nm, or from about150 nm to about 300 nm, or from about 170 to about 240 nm, or from about200 nm to about 240 nm.

Also, as illustrated in FIG. 5A, a transfer system 30 can be coupled tothe drying system 20 in order to transfer substrates into and out of thedrying system 20 and the curing system 10, and exchange substrates witha multi-element manufacturing system 40. Transfer system 30 may transfersubstrates to and from drying system 20 and curing system 10 whilemaintaining a vacuum environment. The drying and curing systems 20, 10,and the transfer system 30 can, for example, include a processingelement within the multi-element manufacturing system 40. For example,the multi-element manufacturing system 40 can permit the transfer ofsubstrates to and from processing elements including such devices asetch systems, deposition systems, coating systems, patterning systems,metrology systems, etc. In order to isolate the processes occurring inthe first and second systems, an isolation assembly 50 can be utilizedto couple each system. For instance, the isolation assembly 50 caninclude at least one of a thermal insulation assembly to provide thermalisolation, and a gate valve assembly to provide vacuum isolation. Thedrying and curing systems 20 and 10, and transfer system 30 can beplaced in any sequence.

IR exposure of the substrate can be performed in the drying system 20,or the curing system 10, or a separate treatment system (not shown).

Alternately, in another embodiment of the invention, FIG. 5B shows aprocessing system 100 for treating a dielectric film on a substrate. Theprocessing system 100 includes a “cluster-tool” arrangement for a dryingsystem 110, and a curing system 120. For example, the drying system 110can be configured to remove, or reduce to sufficient levels, one or morecontaminants, pore-generating materials, and/or cross-linking inhibitorsin the dielectric film, including, for example, moisture, water,solvent, contaminants, pore-generating material, residualpore-generating material, a weakly bonded side group to thestructure-forming material, pore-generating molecules, fragments ofpore-generating molecules, cross-linking inhibitors, fragments ofcross-linking inhibitors, or any other contaminant that may interferewith a curing process performed in the curing system 120.

Additionally, for example, the curing system 120 can be configured tocure the dielectric film by causing or partially causing cross-linkingwithin the dielectric film in order to, for example, improve themechanical properties of the dielectric film. Furthermore, theprocessing system 100 can optionally include a post-treatment system 140configured to modify the cured dielectric film. For example,post-treatment can include thermal heating. Additionally, for example,post-treatment can include spin coating or vapor depositing another filmon the dielectric film in order to promote adhesion for subsequent filmsor improve hydrophobicity. Alternatively, for example, adhesionpromotion may be achieved in a post-treatment system by lightlybombarding the dielectric film with ions by, for example, exposing thesubstrate to plasma.

Also, as illustrated in FIG. 5B, a transfer system 130 can be coupled tothe drying system 110 in order to transfer substrates into and out ofthe drying system 110, and can be coupled to the curing system 120 inorder to transfer substrates into and out of the curing system 120, andcan be coupled to the optional post-treatment system 140 in order totransfer substrates into and out of the post-treatment system 140.Transfer system 130 may transfer substrates to and from drying system110, curing system 120 and optional post-treatment system 140 whilemaintaining a vacuum environment.

Additionally, transfer system 130 can exchange substrates with one ormore substrate cassettes (not shown). Although only two or three processsystems are illustrated in FIG. 5B, other process systems can accesstransfer system 130 including for example such devices as etch systems,deposition systems, coating systems, patterning systems, metrologysystems, etc. In order to isolate the processes occurring in the dryingand curing systems, an isolation assembly 150 can be utilized to coupleeach system. For instance, the isolation assembly 150 can include atleast one of a thermal insulation assembly to provide thermal isolation,and a gate valve assembly to provide vacuum isolation. Additionally, forexample, the transfer system 130 can serve as part of the isolationassembly 150.

IR exposure of the substrate can be performed in the drying system 110,or the curing system 120, or a separate treatment system (not shown).

Alternately, in another embodiment of the invention, FIG. 5C shows aprocessing system 200 for treating a dielectric film on a substrate. Theprocessing system 200 includes a drying system 210, and a curing system220. For example, the drying system 210 can be configured to remove, orreduce to sufficient levels, one or more contaminants, pore-generatingmaterials, and/or cross-linking inhibitors in the dielectric film,including, for example, moisture, water, solvent, contaminants,pore-generating material, residual pore-generating material, a weaklybonded side group to the structure-forming material, pore-generatingmolecules, fragments of pore-generating molecules, cross-linkinginhibitors, fragments of cross-linking inhibitors, or any othercontaminant that may interfere with a curing process performed in thecuring system 220.

Additionally, for example, the curing system 220 can be configured tocure the dielectric film by causing or partially causing cross-linkingwithin the dielectric film in order to, for example, improve themechanical properties of the dielectric film. Furthermore, theprocessing system 200 can optionally include a post-treatment system 240configured to modify the cured dielectric film. For example,post-treatment can include thermal heating. Additionally, for example,post-treatment can include spin coating or vapor depositing another filmon the dielectric film in order to promote adhesion for subsequent filmsor improve hydrophobicity. Alternatively, for example, adhesionpromotion may be achieved in a post-treatment system by lightlybombarding the dielectric film with ions by, for example, exposing thesubstrate to plasma.

Drying system 210, curing system 220, and post-treatment system 240 canbe arranged horizontally or may be arranged vertically (i.e., stacked).Also, as illustrated in FIG. 5C, a transfer system 230 can be coupled tothe drying system 210 in order to transfer substrates into and out ofthe drying system 210, can be coupled to the curing system 220 in orderto transfer substrates into and out of the curing system 220, and can becoupled to the optional post-treatment system 240 in order to transfersubstrates into and out of the post-treatment system 240. Transfersystem 230 may transfer substrates to and from drying system 210, curingsystem 220 and optional post-treatment system 240 while maintaining avacuum environment.

Additionally, transfer system 230 can exchange substrates with one ormore substrate cassettes (not shown). Although only three processsystems are illustrated in FIG. 5C, other process systems can accesstransfer system 230 including for example such devices as etch systems,deposition systems, coating systems, patterning systems, metrologysystems, etc. In order to isolate the processes occurring in the firstand second systems, an isolation assembly 250 can be utilized to coupleeach system. For instance, the isolation assembly 250 can include atleast one of a thermal insulation assembly to provide thermal isolation,and a gate valve assembly to provide vacuum isolation. Additionally, forexample, the transfer system 230 can serve as part of the isolationassembly 250.

IR exposure of the substrate can be performed in the drying system 210,or the curing system 220, or a separate treatment system (not shown).

At least one of the drying system 10 and the curing system 20 of theprocessing system 1 as depicted in FIG. 5A includes at least twotransfer openings to permit the passage of the substrate therethrough.For example, as depicted in FIG. 5A, the drying system 10 includes twotransfer openings, the first transfer opening permits the passage of thesubstrate between the drying system 10 and the transfer system 30 andthe second transfer opening permits the passage of the substrate betweenthe drying system and the curing system. However, regarding theprocessing system 100 depicted in FIG. 5B and the processing system 200depicted in FIG. 5C, each treatment system 110, 120, 140 and 210, 220,240, respectively, includes at least one transfer opening to permit thepassage of the substrate therethrough.

Referring now to FIG. 6, a drying system 300 is shown according toanother embodiment of the invention. Drying system 300 includes a dryingchamber 310 configured to produce a clean, contaminant-free environmentfor drying a substrate 325 resting on substrate holder 320. The dryingsystem 300 can include a thermal treatment device 330 coupled to dryingchamber 310, or to substrate holder 320, and configured to evaporatecontaminants, such as for example moisture, water, residual solvent,etc., by elevating the temperature of substrate 325. Furthermore, thedrying system 300 can include a microwave treatment device 340 coupledto the drying chamber 310, and configured to locally heat contaminantsin the presence of an oscillating electric field. The drying process canutilize the thermal treatment device 330, or the microwave treatmentdevice 340, or both to facilitate drying a dielectric film on substrate325.

The thermal treatment device 330 can include one or more conductiveheating elements embedded in substrate holder 320 coupled to a powersource and a temperature controller. For example, each heating elementcan include a resistive heating element coupled to a power sourceconfigured to supply electrical power. Alternatively, the thermaltreatment device 330 can include one or more radiative heating elementscoupled to a power source and a controller. For example, each radiativeheating element can include a heat lamp coupled to a power sourceconfigured to supply electrical power. The temperature of substrate 325can, for example, range from approximately 20 degrees C. toapproximately 600 degrees C., and desirably, the temperature may rangefrom approximately 200 degrees C. to approximately 600 degrees C. Forexample, the temperature of substrate 325 can range from approximately300 degrees C. to approximately 500 degrees C., or from approximately350 degrees C. to approximately 450 degrees C.

The microwave treatment source 340 can include a variable frequencymicrowave source configured to sweep the microwave frequency through abandwidth of frequencies. Frequency variation avoids charge build-upand, hence, permits damage-free application of microwave dryingtechniques to sensitive electronic devices.

In one example, the drying system 300 can include a drying systemincorporating both a variable frequency microwave device and a thermaltreatment device, such as for example the microwave furnace commerciallyavailable from Lambda Technologies, Inc. (860 Aviation Parkway, Suite900, Morrisville, N.C. 27560).

The substrate holder 320 may or may not be configured to clamp substrate325. For instance, substrate holder 320 may be configured tomechanically or electrically clamp substrate 325.

Further, drying system 300 may include an IR radiation source forexposing the substrate 325 to IR radiation.

Referring again to FIG. 6, drying system 300 can further include a gasinjection system 350 coupled to the drying chamber and configured tointroduce a purge gas to drying chamber 310. The purge gas can, forexample, include an inert gas, such as a noble gas or nitrogen.Additionally, drying system 300 can include a vacuum pumping system 355coupled to drying chamber 310 and configured to evacuate the dryingchamber 310. During a drying process, substrate 325 can be subject to aninert gas environment with or without vacuum conditions.

Furthermore, drying system 300 can include a controller 360 coupled todrying chamber 310, substrate holder 320, thermal treatment device 330,microwave treatment device 340, gas injection system 350, and vacuumpumping system 355. Controller 360 includes a microprocessor, a memory,and a digital I/O port capable of generating control voltages sufficientto communicate and activate inputs to the drying system 300 as well asmonitor outputs from the drying system 300. A program stored in thememory is utilized to interact with the drying system 300 according to astored process recipe. The controller 360 can be used to configure anynumber of processing elements (310, 320, 330, 340, 350, or 355), and thecontroller 360 can collect, provide, process, store, and display datafrom processing elements. The controller 360 can include a number ofapplications for controlling one or more of the processing elements. Forexample, controller 360 can include a graphic user interface (GUI)component (not shown) that can provide interfaces that enable a user tomonitor and/or control one or more processing elements.

Referring now to FIG. 7, a curing system 400 is shown according toanother embodiment of the present invention. Curing system 400 includesa curing chamber 410 configured to produce a clean, contaminant-freeenvironment for curing a substrate 425 resting on substrate holder 420.Curing system 400 further includes one or more radiation sourcesconfigured to expose substrate 425 having the dielectric film toelectromagnetic (EM) radiation at single, multiple, narrow-band, orbroadband EM wavelengths. The one or more radiation sources can includean optional infrared (IR) radiation source 440 and an ultraviolet (UV)radiation source 445. The exposure of the substrate to UV radiation andoptionally IR radiation can be performed simultaneously, sequentially,or over-lapping one another.

The IR radiation source 440 may include a broad-band IR source (e.g.,polychromatic), or may include a narrow-band IR source (e.g.,monochromatic). The IR radiation source may include one or more IRlamps, one or more IR LEDs, or one or more IR lasers (continuous wave(CW), tunable, or pulsed), or any combination thereof. The IR powerdensity may range up to about 20 W/cm². For example, the IR powerdensity may range from about 1 W/cm² to about 20 W/cm². The IR radiationwavelength may range from approximately 1 micron to approximately 25microns. Alternatively, the IR radiation wavelength may range fromapproximately 8 microns to approximately 14 microns. Alternatively, theIR radiation wavelength may range from approximately 8 microns toapproximately 12 microns. Alternatively, the IR radiation wavelength mayrange from approximately 9 microns to approximately 10 microns. Forexample, the IR radiation source 440 may include a CO₂ laser system.Additional, for example, the IR radiation source 440 may include an IRelement, such as a ceramic element or silicon carbide element, having aspectral output ranging from approximately 1 micron to approximately 25microns, or the IR radiation source 440 can include a semiconductorlaser (diode), or ion, Ti:sapphire, or dye laser with optical parametricamplification.

The UV radiation source 445 may include a broad-band UV source (e.g.,polychromatic), or may include a narrow-band UV source (e.g.,monochromatic). The UV radiation source may include one or more UVlamps, one or more UV LEDs, or one or more UV lasers (continuous wave(CW), tunable, or pulsed), or any combination thereof. UV radiation maybe generated, for instance, from a microwave source, an arc discharge, adielectric barrier discharge, or electron impact generation. The UVpower density may range from approximately 0.1 mW/cm² to approximately2000 mW/cm². The UV wavelength may range from approximately 100nanometers (nm) to approximately 600 nm. Alternatively, the UV radiationmay range from approximately 200 nm to approximately 400 nm.Alternatively, the UV radiation may range from approximately 150 nm toapproximately 300 nm. Alternatively, the UV radiation may range fromapproximately 170 nm to approximately 240 nm. Alternatively, the UVradiation may range from approximately 200 nm to approximately 240 nm.For example, the UV radiation source 445 may include a direct current(DC) or pulsed lamp, such as a Deuterium (D₂) lamp, having a spectraloutput ranging from approximately 180 nm to approximately 500 nm, or theUV radiation source 445 may include a semiconductor laser (diode),(nitrogen) gas laser, frequency-tripled (or quadrupled) Nd:YAG laser, orcopper vapor laser.

The IR radiation source 440, or the UV radiation source 445, or both,may include any number of optical device to adjust one or moreproperties of the output radiation. For example, each source may furtherinclude optical filters, optical lenses, beam expanders, beamcollimators, etc. Such optical manipulation devices as known to thoseskilled in the art of optics and EM wave propagation are suitable forthe invention.

The substrate holder 420 can further include a temperature controlsystem that can be configured to elevate and/or control the temperatureof substrate 425. The temperature control system can be a part of athermal treatment device 430. The substrate holder 420 can include oneor more conductive heating elements embedded in substrate holder 420coupled to a power source and a temperature controller. For example,each heating element can include a resistive heating element coupled toa power source configured to supply electrical power. The substrateholder 420 could optionally include one or more radiative heatingelements. The temperature of substrate 425 can, for example, range fromapproximately 20 degrees C. to approximately 600 degrees C., anddesirably, the temperature may range from approximately 200 degrees C.to approximately 600 degrees C. For example, the temperature ofsubstrate 425 can range from approximately 300 degrees C. toapproximately 500 degrees C., or from approximately 350 degrees C. toapproximately 450 degrees C.

Additionally, the substrate holder 420 may or may not be configured toclamp substrate 425. For instance, substrate holder 420 may beconfigured to mechanically or electrically clamp substrate 425.

Referring again to FIG. 7, curing system 400 can further include a gasinjection system 450 coupled to the curing chamber 410 and configured tointroduce a purge gas to curing chamber 410. The purge gas can, forexample, include an inert gas, such as a noble gas or nitrogen.Alternatively, the purge gas can include other gases, such as forexample H₂, NH₃, C_(x)H_(y), or any combination thereof. Additionally,curing system 400 can further include a vacuum pumping system 455coupled to curing chamber 410 and configured to evacuate the curingchamber 410. During a curing process, substrate 425 can be subject to apurge gas environment with or without vacuum conditions.

Furthermore, curing system 400 can include a controller 460 coupled tocuring chamber 410, substrate holder 420, thermal treatment device 430,IR radiation source 440, UV radiation source 445, gas injection system450, and vacuum pumping system 455. Controller 460 includes amicroprocessor, a memory, and a digital I/O port capable of generatingcontrol voltages sufficient to communicate and activate inputs to thecuring system 400 as well as monitor outputs from the curing system 400.A program stored in the memory is utilized to interact with the curingsystem 400 according to a stored process recipe. The controller 460 canbe used to configure any number of processing elements (410, 420, 430,440, 445, 450, or 455), and the controller 460 can collect, provide,process, store, and display data from processing elements. Thecontroller 460 can include a number of applications for controlling oneor more of the processing elements. For example, controller 460 caninclude a graphic user interface (GUI) component (not shown) that canprovide easy to use interfaces that enable a user to monitor and/orcontrol one or more processing elements.

The controllers 360 and 460 may be implemented as a DELL PRECISIONWORKSTATION 610™. The controllers 360 and 460 may also be implemented asa general purpose computer, processor, digital signal processor, etc.,which causes a substrate processing apparatus to perform a portion orall of the processing steps of the invention in response to thecontrollers 360 and 460 executing one or more sequences of one or moreinstructions contained in a computer readable medium. The computerreadable medium or memory for holding instructions programmed accordingto the teachings of the invention and for containing data structures,tables, records, or other data described herein. Examples of computerreadable media are compact discs, hard disks, floppy disks, tape,magneto-optical disks, PROMs (EPROM, EEPROM, flash EPROM), DRAM, SRAM,SDRAM, or any other magnetic medium, compact discs (e.g., CD-ROM), orany other optical medium, punch cards, paper tape, or other physicalmedium with patterns of holes, a carrier wave (described below), or anyother medium from which a computer can read.

The controllers 360 and 460 may be locally located relative to thedrying system 300 and curing system 400, or may be remotely locatedrelative to the drying system 300 and curing system 400 via an internetor intranet. Thus, the controllers 360 and 460 can exchange data withthe drying system 300 and curing system 400 using at least one of adirect connection, an intranet, and the internet. The controllers 360and 460 may be coupled to an intranet at a customer site (i.e., a devicemaker, etc.), or coupled to an intranet at a vendor site (i.e., anequipment manufacturer). Furthermore, another computer (i.e.,controller, server, etc.) can access controllers 360 and 460 to exchangedata via at least one of a direct connection, an intranet, and theinternet.

Furthermore, embodiments of this invention may be used as or to supporta software program executed upon some form of processing core (such as aprocessor of a computer, e.g., controller 360 or 460) or otherwiseimplemented or realized upon or within a machine-readable medium. Amachine-readable medium includes any mechanism for storing informationin a form readable by a machine (e.g., a computer). For example, amachine-readable medium can include media such as a read only memory(ROM); a random access memory (RAM); a magnetic disk storage media; anoptical storage media; and a flash memory device, etc.

Although only certain exemplary embodiments of this invention have beendescribed in detail above, those skilled in the art will readilyappreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention.

1. A method of preparing a porous low dielectric constant (low-k) filmon a substrate, comprising: forming a low-k dielectric film on asubstrate, wherein said low-k dielectric film comprises astructure-forming material and a cross-linking inhibitor; exposing saidlow-k dielectric film to infrared (IR) radiation; and adjusting aresidual amount of said cross-linking inhibitor in order to tune amechanical property of said low-k dielectric film, an electricalproperty of said low-k dielectric film, an optical property of saidlow-k dielectric film, a pore size of said low-k dielectric film, or aporosity of said low-k dielectric film, or a combination of two or morethereof.
 2. The method of claim 1, wherein said cross-linking inhibitorcomprises moisture, water, solvent, contaminants, pore-generatingmaterial, residual pore-generating material, a weakly bonded side groupto the structure-forming material, pore-generating molecules, orfragments of pore-generating molecules, or any combination of two ormore thereof.
 3. The method of claim 1, wherein said cross-linkinginhibitor comprises a pore-generating material, and wherein said formingsaid low-k dielectric film having said structure-forming material andsaid cross-linking inhibitor comprises co-polymerizing astructure-forming molecule and a pore-generating molecule on a surfaceof said substrate.
 4. The method of claim 1, wherein said cross-linkinginhibitor comprises a pore-generating material, and wherein said formingsaid low-k dielectric film having said structure-forming material andsaid cross-linking inhibitor comprises depositing a structure-formingmolecule having a pore-generating molecular side group weakly bonded tosaid structure-forming molecule on a surface of said substrate.
 5. Themethod of claim 1, wherein said adjusting said residual amount of saidcross-linking inhibitor comprises substantially removing saidcross-linking inhibitor from said low-k dielectric film during said IRexposure.
 6. The method of claim 5, wherein said cross-linking inhibitoris substantially removed prior to any exposure of said low-k dielectricfilm to ultraviolet (UV) radiation.
 7. The method of claim 1, whereinsaid adjusting said residual amount of said cross-linking inhibitorcomprises adjusting a time duration for said IR exposure, an IRintensity for said IR exposure, or an IR dose for said IR exposure, or acombination of two or more thereof.
 8. The method of claim 1, whereinsaid mechanical property comprises an elastic modulus (E), or a hardness(H), or both.
 9. The method of claim 1, wherein said electrical propertycomprises a dielectric constant (k).
 10. The method of claim 1, whereinsaid optical property comprises a refractive index (n).
 11. The methodof claim 1, wherein said exposing said low-k dielectric film to IRradiation comprises exposing said low-k dielectric film to polychromaticIR radiation, monochromatic IR radiation, pulsed IR radiation, orcontinuous wave IR radiation, or a combination of two or more thereof.12. The method of claim 1, wherein said exposing said low-k dielectricfilm to IR radiation comprises exposing said low-k dielectric film to IRradiation with a wavelength ranging from approximately 8 microns toapproximately 12 microns.
 13. The method of claim 1, further comprising:exposing said low-k dielectric film to ultraviolet (UV) radiation. 14.The method of claim 13, wherein said exposing said low-k dielectric filmto UV radiation comprises exposing said low-k dielectric film topolychromatic UV radiation, monochromatic UV radiation, pulsed UVradiation, or continuous wave UV radiation, or a combination of two ormore thereof.
 15. The method of claim 13, wherein said exposing saidlow-k dielectric film to UV radiation comprises exposing said low-kdielectric film to UV radiation with a wavelength ranging fromapproximately 200 nanometers to approximately 400 nanometers.
 16. Themethod of claim 13, wherein said UV exposure follows said IR exposure.17. The method of claim 13, wherein said UV exposure occurs during partor all of said IR exposure.
 18. The method of claim 17, wherein said UVradiation comprises exposing said low-k dielectric film to UV radiationwith a wavelength ranging from approximately 300 nanometers toapproximately 450 nanometers.
 19. The method of claim 17, wherein saidadjusting said residual amount of said cross-linking inhibitor comprisesadjusting a time duration for said UV exposure during said IR exposure,a UV intensity for said UV exposure, or a UV dose for said UV exposure,or a combination of two or more thereof.
 20. The method of claim 1,further comprising: exposing said low-k dielectric film to ultraviolet(UV) radiation following said IR exposure; and exposing said low-kdielectric film to second IR radiation during said UV exposure.
 21. Themethod of claim 20, further comprising: exposing said low-k dielectricfilm to third IR radiation following said UV exposure.
 22. The method ofclaim 1, further comprising: exposing said low-k dielectric film tofirst ultraviolet (UV) radiation following said IR exposure; andexposing said low-k dielectric film to second UV radiation during saidIR exposure, wherein said second UV exposure is different than saidfirst UV exposure.
 23. The method of claim 22, wherein said adjustingsaid residual amount of said cross-linking inhibitor comprises adjustinga time duration for said second UV exposure during said IR exposure, aUV intensity for said second UV exposure, or a UV dose for said secondUV exposure, or a combination of two or more thereof.
 23. The method ofclaim 22, wherein said second UV radiation comprises exposing said low-kdielectric film to UV radiation with a wavelength ranging fromapproximately 300 nanometers to approximately 450 nanometers.
 24. Themethod of claim 1, further comprising: heating said substrate beforesaid IR exposure, during said IR exposure, or after said IR exposure, orany combination of two or more thereof.
 25. The method of claim 1,wherein said structure-forming material comprises diethoxymethylsilane(DEMS).